High intensity projector lamp and arc



Aug. 30, 1938. T. o. HALL HIGH INTENSITY PROJECTOR LAMP AND ARC FiledFeb. 5, 1934 4 Sheets-Sheet l INVENTR; 72/5000 MONEY R50. //'LL 7 Aug.30, 1938. T. o. HALL v 2,128,743

HIGH INTENSITY PROJECTOR LAMP AND ARC Filed Feb. 3. 1934 4 SheetsSheet 2V INVENTOR 7 60 BY fifi-"ODORE/OJ/HLL H/s ATTRNEY Aug. 30, I938. TKO.HALL HIGH INTENSITY PROJECTOR LAMP AND ARC 4 Sheets-Sheet 3 Filed Feb.5, 1934 INVENTOR H16 ATTbR'NEY Aug. 30, 1938. T. o. HALL HIGH INTENSITYPROJECTOR LAMP AND ARC 4 Sheets-Sheet 4 Filed Feb. 3, 1954 I f/HLL 7WMATTORNEY INVENTOR 7i-IEODORE 0 Patented Aug. 30, 1938 UNITED STATES2,128,743 HIGH INTENSITY IIRRCEJECTOR LAltfl AND Theodore 0. Hall, LosAngeles, Calif., assignor to Hall & Connolly, Inc., New York, N. Y., acorporation of New York Application February 3, 1934, Serial No. 109,659

' 4 Claims. (01. 176-51) This invention relates to high intensityflaming arc lights especially adapted for projection purposes, such asthe projection of motion pictures. Projection lamps using the directlight from the crater of the positive electrode, which is collected bycondenser lenses, have many advantages oyer the reflector typeprojection lamp in which the light rays are first collected and I thenreflected by a comparatively large parabolic 1O reflector, because thequality of the light is superior in the former type and the shape of theprojected beam is better suited to the objective lens and a largeportion of the heat of the light is absorbed in the thick condenserlenses. In or- 15 der to collect sufiicient light in the direct system,I find it desirable to move the light source very close to the condenserand in order to do this I have devised a new form of high intensity lampin which the negative electrode is placed in a 2 plane at right anglesto and closely adjacent the tip of the positive electrode and alsopreferably lies at a substantial angle to the perpendicular.

In addition, I have devised a novel mechanism for burning andcontrolling this type of arc especially suited for projector lamppurposes.

25 Referring to the drawings showing one form my invention may assume:

Fig. 1 is an exterior view of a complete proector lamp with a housingsurrounding the same.

30 I Fig. 2 is a view illustrating the burning of my new form of highintensity are.

Fig. 3 is a detail of the feeding and rotating means for the positiveelectrode.

Fig. 4 is a side elevation ofthe lamp mecha- 39 nism.

Fig. 5 is a rear elevation of the control mechanism, as mounted on theoutside of the rear door, the rear cover of the control box having beenremoved.

Fig. 6 is a sectional detail of the arc image producing means.

Fig. 7 is a front view of the same.

Fig. 8 is a front view of the lamp.

Fig.- 9} is a detail of the electrode gripping 45 means which rotatesand feeds the positive electrode.

Fig. 10 is a' vertical section of the forward portion of the positiveelectrode holder showing the feeding and rotating means.

Fig. 11 is a sectional detail of the negative electrode holder.

Fig. 12 is an elevation, partly in section, of the rear door viewed fromthe opposite side from C at the bottom of the positive crater.

way the are, when first struck and before the core is heated, takescurrent from the shell, then when the core becomes sufficiently hot sothat I vapor is issued from thev same, the path of the In this currentshifts from the shell to the core with a resultant suddenincrease ofbrilliancy. The are then burns very steadily and at extremely low arcvoltage with a short, rather opaque, flame streaming out of the crater.Preferably also the positive electrode is rotated in steps and so timedwith reference to the consumption of the carbon that the portion of thecarbon crater edge adjacent to the negative tip burns, away more thanthe rest of the crater rim, thus forming a slight hollow opposite thenegative tip. The result is that the other two-thirds of the negativecrater edge over-hang the negative tip and in this way a clearance spaceis provided so that the negative,tip can approach the positive core muchcloser than would be otherwise possible. With this method of burning theare, high intensity results maybe secured with as low a voltage drop as25 volts with 40 ampere current.

My preferred lamp construction for burning this are is shown in generalin Figs. 4 and 5. The positive electrode I is shown as mounted in aholder 2 so that its axis lies in the axis of the condenser lens 3.Current may be led into the electrode by heavy spaced split conductingblocks 4 and 5 which may lie one pair in front of and the other behindthe gearing 6 for rotating the electrode. Such rotation is shown assecured from a shaft 1 operated by mechanism hereinafter described. Saidshaft slowly rocks back and forth a pair of pinions 8 and '9. The formeris not rigidly secured to said shaft but is coupled to the same througha spring 8 which is coupled at its outer end to a sleeve secured to saidshaft (Figs. 4 and 10). Said Pinion 8 meshes with a segmental gear I0secured to a sleeve ll while pinion'S, rigidly secured to shaft 1,meshes with a segmental gear l2 secured to an outer sleeve l3 journalledin the open framework I4. The inner of said sleeves l l is shown ashousing within its forward extension a plurality of rollers I5, whilethe outer sleeve I3 is expanded at its outer end to form a head l8enclosing the rollers. The inner surface of said head I6 is formed witha plurality of cam surfaces I'l, one

for each roller .(Fig. 9). When the two sleeves are relatively rotatedin opposite directions, the rollers wedge and grip the carbon. When,however, this relative rotation is reversed, the carbon is released.Therefore, as the shaft 1 is oscillated the electrode will be given astep-by-step rotation. The pinion 8 is biased in the direction to causethe rollers to grip the carbon in one direction and to release it in theother.

If at the same time the pinion shaft is thrust forward each time that itturns in the direction to grip the carbon, a combination of bothrotation and feed will result. For feeding and rotating the positiveelectrode an extension of the shaft 1 is shown as oscillated by means ofa pinion l'l' thereon which meshes with a short rack l8 secured to aslide l9. Said slide is recipro cated from a pinion 20 on shaft 2!rotated from a power motor 22. Hand rotation and feed of the positiveelectrode may be effected through I the handwheel 6| which may turn theshaft 2| of the pinion 20. Said pinion is shown as turninga gear 23having an eccentric pin 24 thereon which engages a slot in the undersurface of slide l9 to reciprocate the latter as the gear is revolved.Preferably the feed is actuated from this reciprocating motion of theslide l9. This is accomplished by giving the slide I9 a slight motionforward and backward with respect to the shaft 1 as it reciprocateslaterally. One method of securing this result is by connecting the slideI9 to a second slide 25 by means of pivoted links 26 and 21. Since theslide 25 cannot move axially by reason of the pin and slot connections21, 29, the slide l9 will move in an are having a component axially ofshaft 1, the extent of axial movement depending upon the relativelateral positions of the two ends of the links 26 and 21. The fartherthe upper pivot is offset with respect to the lower pivot, the greaterthe feed motion will be. The position of slide 25 in one direction isaccordingly varied to suit the burning conditions by means of threadedshaft 28' operated from thumb piece 29. As an electro-magnet 30 may beprovided to vary the feed from slow to fast feed when the lamp isoperated with a control relay. To this end the magnet 30 is shown asprovided with an armature 3| pivoted at 32, said armature having aroller 33 adapted to engage the far end of the slide 25 for holding theslide against the threaded stop shaft 28' when the magnet is excitedagainst the action of the spring 34. The slight axial movement of theslide l9 may be imparted to the shaft 1 by means of a strap 35 extendingover shaft 1 and between two collars 36, 36' secured to the shaft.Obviously the electrode may be fed in either direction by adjustingslide or plate 25.

The negative electrode holder is shown as comprising inner and outersleeves 40 and 4|, the former being split part way down its length andthreaded at its rear end into the outer sleeve. Said sleeves havecooperating conical surfaces 42 adjacent the are so that the electrodemay be tightly gripped. If desired, a thin inner split sleeve 43 may beinserted between the sleeve 40 and the electrode near its end. The outersleeve is shown as having rack teeth 44 along one side with which meshesa pinion 45 to feed the electrode. Current is led into the same throughcopper ribbon I20 and clamp l2l. Said pinion is mounted on a shaft 46journalled in the bracket 41 and having a universal connection with ashaft 48 leading through universal joint 49 to the shaft in entering thecontrol box. The bracket 41 is shown as supported on an arm 5| pivotedat 52 and oscillated from striking magnet 53. It should be noted thatthe swinging of this arm in striking the are is such that the negativetip travels in an arc the cord of which lies at about 45 degrees to theaxis of the positive electrode. Such a movement of the negative instriking this type of arc is important to prevent the carbons frommissing each other on the back stroke. From Fig. 8 it will also beobserved that the negative not only lies in a plane perpendicular to theaxis of the positive but also that it lies at an acute angle in saidplane to aid in recarboning and to facilitate using a standard lengthcarbon.

For controlling the negative feed, I employ a friction or over-runningclutch or ratchet 54 which drives the negative feed shaft 50 in stepsthrough Worm 5|. Said clutch is operated from the shaft 2| which isdriven from the motor through one-way clutch 65, the lower clutch facebeing secured to a wormwheel (not shown) turned from a worm 66 on theshaft 61 of said motor. On the lower end of the shaft 23' of gear 23 isa disc carrying an eccentric pin 10 which reciprocates slide H (Fig. 5and Fig. 15), which has a slot in the other end thereof engaging a pin12 on the disc 13 forming one element of the one-way ball or rollerclutch 5d. The driven element of said clutch turns the worm 5| drivingthe wormwheel 5| on shaft 55.

The clutch or ratchet is accurately controllable as to length of stroke,since in this type of are it is of the utmost importance that thenegative tip hold its proper position with relation to the crater. Onthe other hand, the consumption of the negative electrode isnot greatlyaffected by variations of current, since with my method of controllingthe positive electrode by the arc wattage, the speed of the motor bearsa definite relation to negative electrode consumption at varyingcurrents.

The control relay is preferably made responsive to variations in bothare current and are 1 voltage and acts to close the circuit through themagnet 30 described above. The relay magnet is shown as comprising anarmature 56 pivoted tact 59', and 60 extending downwardly in saidfigure. The armature is pivoted at El to the central upright portion ofthe T-shaped iron framework of the magnet and is centralized by spring6!). Suitable stops may be provided to limit the control of the armaturein each direction to determine the characteristic of the relay. Movingthe stops to tilt the armature in a direction to shorten the gap at theshunt and to lengthen it at the series coil causes the relay to shortenthe are as the arc current increases. The relay is preferably adjustedso that increase of current lengthens the are slightly but theadjustment may be made so that it will maintain a constant arc gap forwide variations in current. The are gap may also be regulated by thumbpiece operating a small rheostat 81 in circuit with a shunt coil 58 onthe relay. It should also be noted that in my type of are no thermostator other means is needed for maintaining the positive crater in theproper position with respect to col- F lector lens since the fixedposition of the negative with respect to the axis of the positivedetermines the position of the positive crater when the feed of thelatter is properly controlled.

The main support for the lamp is formed by a the entire lamp may tubularbase or hollow horizontal standard 62 to which all parts of the lampproper are secured. Said frame may be provided with exhaust vents atvarious locations along the lamp to cool the mechanism. Said base hassecured to the rear end thereof a V-shaped casting I2 which is supportedfrom the main base plate or upright I3 by a three point supportcomprising three threaded shafts I4, and 16 (Fig. 12). Each of saidshafts is provided with a thumb piece 11 so that the position of thelamp, both toward and away from the collector lens and also laterally,may be quickly and accurately adjusted. Helical springs 18 are shown totake up the lost motion in the threads. The extensions of the feedshafts 1 and pass through said plate I3 and into the control box.Preferably an air vent I22 and I23 is placed under each contact member 4and 5 to cool the same.

The entire control box may be hinged to the frame by hinge pins I9 andso that by taking out the locking bolts the control box may be swungoutwardly with the lamp attached thereto to swing the lamp toward one ofthe doors 80 of the main housing SI for recarboning. The back plate I3,together with the entire lamp'mechanism secured thereto, may be liftedupwardly to lift the hinge pins 19, 80 out of the hinge sockets Ill, Illon the lamp housing so that be slid out backward from the housing. Theoutlet of the blower 8I mounted on the motor shaft is provided with alarge pipe 82 which loosely enters the end of the hollow base 52. Air,therefore, passes through said base and the main portion thereof isdischarged from a long narrow slot 83 in a flat upwardly bent noseagainst the inner surface of the collector lens 3 to cool the same andact as an air curtain between the arc and lens to prevent pitting of thelens by hot particles and also to bend the arc flames away from the lensand aid in maintaining the high intensity are.

Preferably also the lens holder 84 is adjustably mounted in front of theare. As shown it is supported on trunnions 85, 85 in a bracket 86pivoted on shaft -B'I at the base, the entire bracket being adjustableabout said pivot by means of threaded shaft 88 and knob thereon. Undersaid lens holder is pivotally mounted a curved member 89 (Fig. 13)pivoted in bracket 86 on axis 90, 90. Rising from said member on oneside is an arm 9I having a pin 92 thereon passing through a slot 93 inbracket 88 to engage a threaded block 94 threaded on a shaft 95 foradjustment. The holder is also provided with a lug 96 which engages saidloop at least on one side. By adjusting either or both of shafts 88, 95it will readily be apparent that the lens holder may be moved to andfrom the arc with or without tilting the same.

For obtaining a view of the are from without the housing 81, I haveshown a small ground glass window I00 at the end of a tube IIII whichextends from a point within the housing above and to one side of the arethrough and without the housing 8i (Fig. 1) so that the arc image may beviewed on the finder. The tube is shown as having at its forward end asmall peep hole I02 which throws an arc image on the reflector I03 whichreflects the image on the window I00. Said tube may be supported at itsforward end by a rod I04 which extends through-the forward end of thecasing and may be provided with an adjusting knob I05 so as to positionthe aperture I02 in the proper location with respect to the arc. The

lamp housing is shown as of generally octagonal shape contrary to theusual cylindrical shape. A

mark I06 may be provided on the ground glass finder for aiding inlocating the arc.

There also may be provided the usual shutter I01 for protecting thecondenser lens system in striking the arc, etc. As shown, said shutteris in the form of a disc fixed to an arm I 08 mounted on a shaft I09which is rotated by means of crank handle IIO.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle and operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.Also, while it is designed to use the various features and elements inthe combination and relations described, some of these may be alteredand others omitted without interfering with the more general resultsoutlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. In a high intensity projector, the combination with the positiveelectrode holder, of means for rotating and feeding the electrodetherethrough comprising a slide, means for continuously reciprocatingthe same, a shaft oscillated thereby, a roller grip clutch on saidholder and oscillated by said shaft for gripping the electrode whenturned one way and releasing it when turned the other way to rotate theelectrode step by step, and means for moving said slide slightly to andfro in the direction of said shaft as it reciprocates whereby theelectrode is both rotated and fed.

2. In a high intensity projector, the combination with the positiveelectrode holder, of means for rotating and feeding the electrodetherethrough comprising a slide, means for continuously reciprocatingthe same, a shaft oscillated thereby, a roller grip clutch on saidholder and oscillated by said shaft for gripping the electrode whenturned one way and releasing it when turned the other way to rotate theelectrode step by step, means for moving said slide slightly to and froin the direction of said shaft as it reciprocates, and means for varyingthe extent of said to and fro motion in accordance with the arc lengthto regulate the feed.

3. Ina projector lamp having a main housing, a hinged rear doortherefor, a motor on the outside of said door for variable speed drivesand ventilating, feeding means also on said door driven by said motor,electrode holders and a common support therefor secured to the inside ofsaid door including a hollow horizontal standard for the cooling airpassing from the motor, shafts thereon driven from said variable speeddrives for feeding the electrodes, and current introducing brushes onsaid holders, said support having vents therein for cooling said brushesand holders. 4. In a projector lamp, a lamp housing, a feeding andventilating motor at the rear thereof, spaced electrode holders, ahollow horizontal standard for supporting said electrode holders andhaving vents therein for cooling said holders, a projector lens, and aforward nozzle-like part on said standard for directing air on said lensto cool the same.

THEODORE 0. BALL.

